Chevy Cobalt Forum banner
1 - 6 of 6 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter · #1 ·
Hello!

Disclaimer, not a mechanic. Just trying to get a bit more life from my trusty Cobalt since now is not a great time to be investing in a new car.

Basically, whenever I'm coming to a stop the speedometer may jump up to 30-40mph and the RPMs will spike. More often than not the car stalls. I've also noticed this occurring when shifting to reverse.

No check engine light or codes.

Here's a video of it in action:

So far, I've done the following:

  • Cleaned throttle body
  • Cleaned mass air flow sensor
  • Replaced the PCV valve hose with OEM (noticed that this was severely damaged while performing the other stuff)

Some research pointed me towards needing to "relearn the idle position" after cleaning the throttle body. I attempted the steps I found and just had the car on a pretty decent highway drive. Stalled out a few times making it to the highway ramp, but after getting a good 30-40 minute drive it was much better on the way home. Meters still jumped a few times coming to a stop on my way back, but no stalls.

Excuse the ignorant question, but could it be something electrical related? Right around when this started happening I noticed that my radio would randomly change stations and the dials would not work until I powered the radio off and back on again.

Any help or guidance would be greatly appreciated!
 

·
Registered
Joined
·
3 Posts
Hello!

Disclaimer, not a mechanic. Just trying to get a bit more life from my trusty Cobalt since now is not a great time to be investing in a new car.

Basically, whenever I'm coming to a stop the speedometer may jump up to 30-40mph and the RPMs will spike. More often than not the car stalls. I've also noticed this occurring when shifting to reverse.

No check engine light or codes.

Here's a video of it in action:

So far, I've done the following:

  • Cleaned throttle body
  • Cleaned mass air flow sensor
  • Replaced the PCV valve hose with OEM (noticed that this was severely damaged while performing the other stuff)

Some research pointed me towards needing to "relearn the idle position" after cleaning the throttle body. I attempted the steps I found and just had the car on a pretty decent highway drive. Stalled out a few times making it to the highway ramp, but after getting a good 30-40 minute drive it was much better on the way home. Meters still jumped a few times coming to a stop on my way back, but no stalls.

Excuse the ignorant question, but could it be something electrical related? Right around when this started happening I noticed that my radio would randomly change stations and the dials would not work until I powered the radio off and back on again.

Any help or guidance would be greatly appreciated!
My 2010 cobalt is doing the same thing. Have you figured out exactly what the issue was with yours?
 

·
Registered
Joined
·
129 Posts
I know this is an old thread now, but the OP video seems to show an electrical/computer issue. The speedometer needle jumps as soon as the engine dies.
 

·
Registered
Joined
·
5 Posts
I know this is an old thread now, but the OP video seems to show an electrical/computer issue. The speedometer needle jumps as soon as the engine dies.
Did you figure out what the cause is? The dog learned some new words tonight when he went with me to haul the trash off - speedometer needle jumps, car idles down and dies. It starts back up but getting it back into Drive and going is a problem as it wants to keep dying.
 

·
Registered
Joined
·
33 Posts
Have you tried reseating the 2 BCM modules in the passenger side fuse panel? If you have no codes it sounds like a electrical issue. A lot of electrical glitches on these cars are solved by doing that.

If that does not fix things and you still have no codes. If you live in the rust belt like i do I would then check the various ground locations on the car. There used to be extensive guides here to where they all are, but a lot of the pictures are no longer available here, but you can find them all using google.

Good luck as intermittent electrical gremlins with no codes like you have are a pain.
 
1 - 6 of 6 Posts
Top